Generally, lamps or lighting systems utilize some form of photocell control for activating and deactivating the outdoor lighting based upon day and night conditions. Particularly, the photocell is used to sense ambient lighting from the sun, turn on the lighting when the sunlight is below a certain level, and turn off the lighting when the sunlight is above a certain level. More specifically, all the landscape lighting systems are normally powered by 12 volts (V) alternating current (AC) by means of a transformer which converts an AC household power input (typically 120 V AC) to the 12 Volts AC. The transformer is an essential element owing to the power input specifications of the various lighting elements which make up the lighting systems. However, this method may leave lights on longer than necessary before turning them off in the morning.
Lamps or lighting systems are available with automatic on and off mechanism. Examples of such products are street light or building façade lights. Conventionally, setting up the on/off control of lamps or lighting systems has been achieved in a number of different ways, these including installing a timer on the primary winding of the transformer. Particularly, the timer set is used to turn on the lights at a particular time and turn them off at a second particular time. However, simple timer assemblies requires frequent readjustment particularly following power outages and further that the transformer must be located in an area accessible to the user in order to make the necessary adjustments. Moreover, as the day's progress and sunrise and sunset times change, the timer must be reset frequently.
Currently, existing street light utilizes a photo sensor to sense the ambient light condition. If the ambient light condition drops below a certain level, the street light will turn on. Similarly when the ambient light condition is above a certain level, the street light will turn off. However given the resources and maintenance cost, the street light and sensors are not maintained regularly, calibrated or replaced. As a result, it is often observed that many street lights are still on when it is already bright outside in day light or many street lights are still off when it is dark outside. Consequently, this results in number of accidents on road. Moreover, street lamps are still on when it is not suppose to or when it is bright light in day time which results in wastage of energy.
As it is well known in the art, various street lights that are turn on or off automatically are controlled by photo sensors. More specifically, when the sensor detects low ambient light, it triggers the lamp to turn on. However, the problem is that the sensors become faulty or degrade over time and need to be replaced or calibrated. Replacing or calibrating the sensors requires a lot of effort, resources, time and money. In practice, if it is required to calibrate or replace all the sensors for each street light for the entire state or country is a cumbersome task to perform. In many situations street lights are located in remote areas. For this reason many of the street light sensors do not get maintained. As a result, it is not uncommon to see street lights that have not turned on when it is already dark or see street lights that are still on when it is already bright outside. When the former occurs, accidents can happen and human lives are at risk. When the latter happens, energy wastage occurs. With the rising cost of electricity multiplied by the number of street lights, the wastage is very substantial.
Another possible method is to use an astronomic time clock to control the timing of the lighting. However, it is necessary to correctly set an astronomic clock.
Outside lighting control is addressed in a variety of patents. U.S. Patent Application 2010/0030389 (Palmer et al) discloses personal computer control of automatic irrigation and lighting systems. A lighting zone can be set in accordance with sunrise and sunset times. Given the location, a forecasting site provides sunrise and sunset data at preset intervals. However, this requires an active connection to the Internet. The schedule can be transmitted by email.
U.S. Pat. No. 7,847,706 (Ross et al) illustrates a lighting control unit using location to calculate sunrise and sunset times. However, this method requires frequent communication with a wireless network.
U.S. Pat. No. 7,571,063 (Howell et al) teaches lighting control and performance monitoring. For example, lights can be turned off or dimmed at an earlier hour on Sunday when a store closes earlier than other days. However, this method depends on setting a timer for particular on and off times.
U.S. Patent Application 2009/0322253 (Buelow II et al) teaches that a command system schedules changes in mode of a LED lighting system based on input from the atomic time clock.
U.S. Pat. No. 8,593,268 (Valetutti, Vincent) teaches a device and method to automatically control timing of outside lighting. Particularly, an ephemeris program and a calendar are loaded into memory on a timing device. The present invention uses a GPS system to determine the physical location. Therefore, a GPS system has to be embedded into the system and have constant communication with the satellite. More specifically, the calendar is loaded into the memory to determine the day. Once the physical location and the day are determined, the on/off time is calculated based on the ephemeris program. An ephemeris is an astronomical chart which provides the relative movement/position of the earth relative to the sun.
Accordingly, there remains a need in the art for system and method to automatically control turning on and off outside lighting systems.